CVE-2026-93227Public exploit

Boot hang via out-of-range deferred memory PFN

Published Sep 24, 2026 · Updated Sep 24, 2026

Memory initialization flaw in Linux 6.18 allows attackers to crash or hang the system through a crafted CMA boot configuration. In mm/mm_init.c, deferred_grow_zone() advances in section-sized chunks and can store pgdat->first_deferred_pfn beyond node RAM instead of the ULONG_MAX completion marker. The condition requires CONFIG_DEFERRED_STRUCT_PAGE_INIT and CONFIG_CMA, a large CMA reservation, non-section-aligned node RAM, and control of boot parameters; deferred_init_memmap() then hits BUG_ON() or leaves boot waiting indefinitely.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory initialization flaw in Linux 6.18 allows attackers to crash or hang the system through a crafted CMA boot configuration. In mm/mm_init.c, deferred_grow_zone() advances in section-sized chunks and can store pgdat->first_deferred_pfn beyond node RAM instead of the ULONG_MAX completion marker. The condition requires CONFIG_DEFERRED_STRUCT_PAGE_INIT and CONFIG_CMA, a large CMA reservation, non-section-aligned node RAM, and control of boot parameters; deferred_init_memmap() then hits BUG_ON() or leaves boot waiting indefinitely.

The record

CVE
CVE-2026-93227
Published
Sep 24, 2026
Updated
Sep 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Sep 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 24, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <45489d4f95802903ab35799b400b346fa4e13151
  2. Affected versionversion=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <84339578c2d6936ac3a93cd1f0bbaa3468a988f2
  3. Affected versionversion=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <97090500d776c3f6d08e857e3a0a7cf092999094
  4. Affected versionversion=6.18

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <45489d4f95802903ab35799b400b346fa4e13151; version=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <84339578c2d6936ac3a93cd1f0bbaa3468a988f2; version=3acb913c9d5bd8dcf61677ccba96d349e7681cf8 <97090500d776c3f6d08e857e3a0a7cf092999094; version=6.18

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

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No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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